Electrical connector

ABSTRACT

A polyester composition prepared by melting and blending a polyester with a glycidyl ester compound, a glycidyl ether compound and a catalyst has good hydrolysis resistance and, when melted, gives little gas generation and undergoes little viscosity change. It is most favorable for parts of automobile, electric and electronic appliances such as connectors.

This application is a division of U.S. patent application Ser. No.09/988,776 filed Nov. 20, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a polyester composition which haveimproved resistant to hydrolytic degradation and which, when melted,gives little gas emission and undergoes little viscosity change.

2. Description of the Related Art

Polyesters, especially polybutylene terephthalate (hereinunder referredto as PBT) have good moldability, good heat resistance, good mechanicalproperties and good chemical resistance, and are therefore widely usedfor various molding materials, for example, for connectors, relays,switches and other parts of automobiles and electric and electronicappliances.

However, PBT is problematic in its hydrolysis resistance. It isconsidered that the hydrolysis resistance of PBT greatly depends on thecarboxyl end group content thereof, and PBT having a reduced carboxylend group content is desired for realizing increased hydrolysisresistance of itself so that it is usable with no problem even in severeenvironments, for example, in high-temperature high-humidityatmospheres.

Various methods for the purpose have been investigated. For example,JP-B27911/1969 discloses a method of adding a phenyl glycidyl ethercompound to a polyester; JP-A 87452/1982 discloses a method of adding amonoglycidyl ester compound thereto; and JP-A 52344/1983 discloses amethod of adding a glycidyl ester compound and a glycidyl ether compoundthereto. However, these methods are all still problematic in that thehydrolysis resistance of the resulting polyesters is not so good and theviscosity in their melts is increased. U.S. Pat. No. 4,229,553, JP-B47804/1988, JP-A287657/1991, U.S. Pat. No. 5,026,790, JP-A287419/1994,JP-A 222279/1993 (U.S. Pat. No. 5,596,049), JP-B 47685/1995 (U.S. Pat.No. 5,300,546) and U.S. Pat. No. 5,731,390 disclose a method of addingan epoxy compound to a polyester and further adding thereto an additivethat serves as a catalyst. However, when an epoxy compound is merelycombined with a specific catalyst for the additive to a polyester, as inU.S. Pat. No. 4,229,553, JP-B 47804/1988, JP-A 287657/1991, U.S. Pat.No. 5,026,790 and JP-A 287419/1994, it could not still producesatisfactory results. When a single, specific epoxy compound is,combined with a catalyst, added to a polyester, as in JP-A 222279/1993(U.S. Pat. No. 5,596,049) , JP-B 47685/1995 (U.S. Pat. No. 5,300,546)and U.S. Pat. No. 5,731,390, the carboxyl end group content of theresulting polyesters decreases and the hydrolysis resistance thereoftherefore increases, but the results are not still satisfactory. Inaddition, the polyesters disclosed involve another problem in that theygive much gas emission when processed or used, and they bleed out whentheir moldings are hydrolyzed. At present, no one has achievedsatisfactory methods for improving polyester.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a polyestercomposition which is highly resistant to hydrolytic degradation andwhich, when melted, gives little gas emission and undergoes littleviscosity change.

The polyester composition of the invention comprises a melt blendedproduct of(a) a polyester, (b) a glycidyl ester compound, (c) a glycidylether compound and (d) a catalyst. This is highly resistant tohydrolysis and, when melted, gives little gas and undergoes littleviscosity change.

Preferred embodiments of the invention are mentioned below.

The polyester composition further contains (e) from 1 to 100 parts byweight, relative to 100 parts by weight of the polyester (a), of animpact modifier;

It further contains (f) from 1 to 100 parts by weight, relative to 100parts by weight of the polyester (a), of a filler;

The carboxyl end group content of the polyester composition is at most 5equivalents/ton;

The glycidyl ester compound (b) has one glycidyl group in the molecule;

The glycidyl ester compound (b) is any of glycidyl esters of saturatedaliphatic monocarboxylic acids or glycidyl esters of aromaticmonocarboxylic acids;

The glycidyl ester compound (b) is glycidyl benzoate or glycidylversatate;

The glycidyl ether compound (c) has one or two glycidyl groups in themolecule;

The glycidyl ether compound (c) is an aromatic glycidyl ether;

The glycidyl ether compound (c) is phenyl glycidyl ether or bisphenol Adiglycidyl ether epoxy resin;

The catalyst (d) is an organic, alkali metal or alkaline earth metalsalt;

The catalyst (d) is a salt of an organic acid having at least 6 carbonatoms with an alkali metal or an alkaline earth metal;

The catalyst (d) is at least one of sodium stearate, potassium stearate,calcium stearate, magnesium stearate and sodium benzoate;

The polyester (a) is a polymer or copolymer obtained throughcondensation of essentially a dicarboxylic acid or its ester-formingderivative with 1,4-butanediol, or their mixture.

The invention also provides a method for producing a polyestercomposition, which comprises melting and blending (a) a polyester with(b) a glycidyl ester compound, (c) a glycidyl ether compound and (d) acatalyst.

The invention further provides a connector made from the polyestercomposition.

Though not clear, the polyester composition of the invention may attainthe good results for the following reasons: A glycidyl ester compound(b) and a glycidyl ether compound (c) that differ in the reactivity withcarboxyl end groups of polyester are combined along with a catalyst (d)and added to a polyester (a). Of the resulting polyester composition,therefore, the increase in the carboxyl end group content will besignificantly retarded owing to not only the reaction of the combinedadditives with the carboxyl end groups originally existing in thepolyester (a) but also the reaction thereof with the carboxyl end groupsadditionally formed through hydrolysis of the polyester (a).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The polyester (a) for use in the invention is a polymer or copolymerobtained through condensation of essentially a dicarboxylic acid (or itsester-forming derivative) with a diol (or its ester-forming derivative),or their mixture.

The dicarboxylic acid component includes, for example, aromaticdicarboxylic acids such as terephthalic acid, isophthalic acid, phthalicacid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylicacid, bis(p-carboxyphenyl)methane, anthracenedicarboxylic acid,4,4′-diphenylether-dicarboxylic acid, 5-sodium-sulfoisophthalic acid;aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaicacid, dodecanedicarboxylic acid; alicyclic dicarboxylic acids such as1,3-cyclohexanedicarboxylic acid; and their ester-forming derivatives.The diol component includes, for example, aliphatic diols having from2to 20 carbon atoms, such as ethylene glycol, propylene glycol,1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol,decamethylene glycol, cyclohexanedimethanol, cyclohexanediol; long-chainglycols having a molecular weight of from 400 to 6000, such aspolyethylene glycol, poly-1,3-propylene glycol, polytetramethyleneglycol; and their ester-forming derivatives.

Preferred examples of their polymers and copolymers are polyethyleneterephthalate, polypropylene terephthalate, polybutylene terephthalate,polyethylene naphthalate, polybutylene naphthalate,polycyclohexylene-dimethylene terephthalate andpolyethylene-1,2-bis(phenoxy)ethane-4,4′-dicarboxylate, as well aspolyethylene isophthalate/terephthalate, polybutyleneterephthalate/isophthalate, polybutylene terephthalate/adipate,polybutylene terephthalate/sebacate, polybutyleneterephthalate/decanedicarboxylate, polyethylene terephthalate/adipate,polyethylene terephthalate/5-sodium-sulfoisophthalate, polybutyleneterephthalate/5-sodium-sulfoisophthalate. One or more of these areemployable herein. Of those, preferred are polyethylene terephthalate,polypropylene terephthalate, polybutylene terephthalate, polyethylenenaphthalate, polybutylene naphthalate, polycyclohexylene-dimethyleneterephthalate, polybutylene terephthalate/adipate, polybutyleneterephthalate/decanedicarboxylate and polyethyleneterephthalate/adipate, in view of the moldability of the polyestercomposition; and more preferred are polybutylene terephthalate, itscopolymers and their mixtures.

Preferably, the polyester (a) has an intrinsic viscosity of from 0.5 to1.5 dl/g, measured in orthochlorophenol to have a concentration of 0.5%at 25° C.

The glycidyl ester compound (b) for use in the invention is a compoundhaving an esterified glycidyl group, and its examples are glycidylbenzoate, glycidyl p-toluate, glycidyl cyclohexanecarboxylate, glycidylstearate, glycidyl laurate, glycidyl palmitate, glycidyl versatate,glycidyl oleate, glycidyl linolate, glycidyl linolenate, diglycidylterephthalate, diglycidyl isophthalate, diglycidyl phthalate, diglycidylnaphthalenedicarboxylate, diglycidyl bibenzoate, diglycidylmethylterephthalate, diglycidyl hexahydrophthalate, diglycidyltetrahydrophthalate, diglycidyl cyclohexanedicarboxylate, diglycidyladipate, diglycidyl succinate, diglycidyl sebacate, diglycidyldodecanedicarboxylate, diglycidyl octadecanedicarboxylate, triglycidyltrimellitate, tetraglycidyl pyromellitate. One or more of these may beused herein. Especially preferred are glycidyl ester compounds havingone glycidyl group in the molecule in view of their melt viscositystability; more preferred are glycidyl esters of saturated aliphaticmonocarboxylic acids and glycidyl esters of aromatic monocarboxylicacids; and even more preferred are glycidyl benzoate and glycidylversatate.

The amount of the glycidyl ester compound (b) to be in the polyestercomposition preferably falls between 0.1 and 3 parts by weight, morepreferably between 0.1 and 2 parts by weight, even more preferablybetween 0.3 and 1.5 parts by weight, relative to 100 parts by weight ofthe polyester therein.

The glycidyl ether compound (c) for use in the invention is a compoundhaving an etherified glycidyl group, and its examples are butyl glycidylether, stearyl glycidyl ether, allyl glycidyl ether, phenyl glycidylether, o-phenylphenyl glycidyl ether, ethyleneoxide lauryl alcoholglycidyl ether, ethyleneoxide phenol glycidyl ether, ethylene glycoldiglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycoldiglycidyl ether, polypropylene glycol diglycidyl ether, neopentylglycol diglycidyl ether, polytetramethylene glycol diglycidyl ether,cyclohexanedimethanol diglycidyl ether, glycerol triglycidyl ether,trimethylolpropane triglycidyl ether, pentaerythritol polyglycidylether, and bisphenol A diglycidyl ether epoxy resins, bisphenol Fdiglycidyl ether epoxy resins and bisphenol S diglycidyl ether epoxyresins obtained through condensation of bisphenols such as2,2-bis-(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)methane,bis(4-hydroxyphenyl) sulfone, with epichlorohydrin. One or more of thesemaybe used herein. Especially preferred are glycidyl ether compoundshaving one or two glycidyl groups in the molecule in view of their meltviscosity stability; more preferred are aromatic glycidyl ethers; andeven more preferred are phenyl glycidyl ether and bisphenol A diglycidylether epoxy resins.

The amount of the glycidyl ether compound (c) to be in the polyestercomposition preferably falls between 0.1 and 5 parts by weight, morepreferably between 0.5 and 3 parts by weight, even more preferablybetween 1.0 and 2.5 parts by weight, relative to 100 parts by weight ofthe polyester therein.

The catalyst (d) for use in the invention is a compound having theability to promote the reaction of the glycidyl group with the carboxylend group of the polyester (a), and its examples are alkali metalcompounds such as sodium hydroxide, potassium hydroxide, lithiumhydroxide, cesium hydroxide, sodium hydrogen carbonate, potassiumhydrogen carbonate, sodium carbonate, potassium carbonate, lithiumcarbonate, sodium acetate, potassium acetate, lithium acetate, sodiumstearate, potassium stearate, lithium stearate, sodium borohydride,lithium borohydride, sodium phenylboron, sodium benzoate, potassiumbenzoate, lithium benzoate, disodium hydrogenphosphate, dipotassiumhydrogenphosphate, dilithium hydrogenphosphate, disodium, dipotassiumand dilithium bisphenol A, sodium, potassium, lithium and cesiumphenoxide; alkaline earth metal compounds such as calcium hydroxide,barium hydroxide, magnesium hydroxide, strontium hydroxide, calciumhydrogencarbonate, barium carbonate, magnesium carbonate, strontiumcarbonate, calcium acetate, barium acetate, magnesium acetate, strontiumacetate, calcium stearate, magnesium stearate, strontium stearate;tertiary amines such as triethylamine, tributylamine, trihexylamine,triamylamine, triethanolamine, dimethylaminoethanol, triethylenediamine,dimethylphenylamine, dimethylbenzylamine, 2-(dimethylaminomethyl)phenol,dimethylaniline, pyridine, picoline, 1,8-diazabicyclo(5,4,0undecene-7;imidazole compounds such as 2-methylimidazole, 2-ethylimidazole,2-isopropylimidazole, 2-ethyl-4-methylimidazole,4-phenyl-2-methylimidazole; quaternary ammonium salts such astetramethylammonium chloride, tetraethylammonium chloride,tetrabutylammoniumbromide, trimethylbenzylammoniumchloride,triethylbenzylammonium chloride, tripropylbenzylammonium chloride,N-methylpyridinium chloride; phosphine compounds such astrimethylphosphine, triethylphosphine, tributylphosphine,triocytlphosphine; phosphonium salts such as tetramethylphosphoniumbromide, tetrabutylphosphonium bromide, tetraphenylphosphonium bromide,ethyltriphenylphosphonium bromide, triphenylbenzylphosphonium bromide;phosphates such as trimethyl phosphate, triethyl phosphate, tributylphosphate, trioctyl phosphate, tributoxyethyl phosphate, triphenylphosphate, tricresyl phosphate, trixylenyl phosphate, cresyldiphenylphosphate, octyldiphenyl phosphate, tri(p-hydroxy)phenyl phosphate,tri(p-methoxy)phenyl phosphate; organic acids such as oxalic acid,p-toluenesulfonic acid, dinonylnaphthalenedisulfonic acid,dodecylbenzenesulfonic acid; Lewis acids such as boron trifluoride,aluminium tetrachloride, titanium tetrachloride, tin tetrachloride. Oneor more of these may be used herein. Especially preferred are alkalimetal compounds, alkaline earth metal compounds and phosphates; and morepreferred are salts of organic acids with alkali metals or alkalineearth metals. Concretely, preferred examples of the compounds are sodiumstearate, potassium stearate, calcium stearate, magnesium stearate,sodium benzoate, sodium acetate, potassium acetate, calcium acetate andmagnesium acetate. Even more preferred are organic salts having at least6 carbon atoms of alkali metals or alkaline earth metals, such as sodiumstearate, potassium stearate, calcium stearate, magnesium stearate andsodium benzoate and using at least one of the compounds is preferredherein.

The amount of the catalyst (d) to be in the polyester composition is notspecifically defined, but preferably falls between 0.001 and 1 part byweight, more preferably between 0.01 and 0.1 parts by weight, even morepreferably between 0.03 and 0.1 parts by weight, relative to 100 partsby weight of the polyester therein. If the catalyst amount is smallerthan 0.001 parts by weight, the hydrolysis resistance of the polyestercomposition will be poor; but if larger than 1 part by weight, it willcause side reactions and the deterioration in the physical properties ofthe composition will be nonnegligible.

An impact modifier (e) may be added to the polyester composition forimproving the mechanical strength and other properties of thecomposition. The impact modifier (e) may be any and every one known forpolyester, concretely including natural rubber, polyethylene such aslow-density polyethylene and high-density polyethylene, polypropylene,high-impact polystyrene, polybutadiene, styrene-butadiene copolymer,ethylene-propylene copolymer, ethylene-methyl acrylate copolymer,ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer,ethylene-glycidyl methacrylate copolymer, polyethyleneterephthalate-poly(tetramethyleneoxide)glycol block copolymer, andpolyethylene terephthalate/isophthalate-poly(tetramethyleneoxide)glycolblock copolymer. One or more of these may be used herein.

The amount of the impact modifier (e) to be in the polyester compositionmay fall between 0.1 and 100 parts by weight, preferably between 1 and50 parts by weight, relative to 100 parts by weight of the polyestertherein.

A filler (f) may also be added to the polyester composition forimproving the mechanical strength and other properties of thecomposition. Its type is not specifically defined, and any of fibrous,tabular, powdery or granular fillers may be used herein. Concretely, itincludes fibrous or whisker-like fillers, for example, glass fibers,PAN-derived or pitch-derived carbon fibers, metal fibers such asstainless steel fibers, aluminium fibers and brass fibers, organicfibers such as aromatic polyamide fibers, as well as gypsum fibers,ceramic fibers, asbestos fibers, zirconia fibers, alumina fibers, silicafibers, titanium oxide fibers, silicon carbide fibers, rockwool,potassium titanate whiskers, barium titanate whiskers, aluminiumboratewhiskers, silicon nitride whiskers; and powdery, granular or tabularfillers such as mica, talc, kaolin, silica, calcium carbonate, glassbeads, glass flakes, glass microballoons, clay, molybdenum disulfide,wollastonite, montmorillonite, titanium oxide, zinc oxide, calciumpolyphosphate, graphite. Of those, especially preferred are glassfibers. Their type is not specifically defined, and any ordinary glassfibers for reinforcing resin are usable herein. For example, the glassfibers for use herein may be selected from chopped strands of long orshort glass fibers, and milled fibers thereof. Two or more of theabove-mentioned filler substances may be combined for the filler (f) foruse herein. If desired, the filler (f) may be processed on its surfacewith any known coupling agent (e.g., silane coupling agent, titanatecoupling agent) or with any other surface-treating agent. The glassfibers for use herein may be coated or bundled with thermoplastic resinsuch as ethylene-vinyl acetate copolymer or with thermosetting resinsuch as epoxy resin.

The amount of the filler (f) to be in the polyester composition may fallbetween 0.1 and 100 parts by weight, preferably between 1 and 50 partsby weight, relative to 100 parts by weight of the polyester therein.

Not interfering with the object of the invention, one or more ordinaryadditives may be added to the polyester composition of the invention.The additives include, for example, flame retardant, nucleating agent,UV absorbent, thermal stabilizer, lubricant, mold release agent,colorant (e.g., dye, pigment). Limited to a small amount, any otherthermoplastic resin (e.g., polyamide, polyacetal, polycarbonate) andthermosetting resin (e.g., phenolic resin, melamine resin, siliconeresin) may be added to the polyester composition.

Though not specifically defined, the method for producing the polyestercomposition of the invention comprises at least a step of melting andkneading the polyester (a) together with the glycidyl ester compound(b), the glycidyl ether compound (c) and the catalyst (d). Preferably,the polyester (a), the glycidyl ester compound (b), the glycidyl ethercompound (c), the catalyst (d) and other optional additives are blendedin dry, and then blended in melt in an extruder at a temperature notlower than the melting point of the polyester (a); or using an extruderequipped with two supply hoppers, the polyester (a), the glycidyl estercompound (b), the catalyst (d) and other optional additives are fed intothe extruder through the main supply hopper disposed just before thescrew, while the glycidyl ether compound (c) is thereinto through theside supply hopper disposed between the main supply hopper and the endof the extruder, and they are all melted and blended in the extruder.

The resulting composition may be shaped in any ordinary known method of,for example, injection molding or extrusion.

For the first factor to improve the hydrolysis resistance of thepolyester composition of the invention, it is important that theglycidyl ester compound (b) and the glycidyl ether compound (c) whichdiffer in the properties such as the reactivity with the carboxyl endgroups of polyester are combined along with the catalyst (d) to therebyreduce the carboxyl end groups originally existing in the polyester (a)through the reaction of (b) and (c) with them. From this viewpoint, itis desirable that the carboxyl end group content of the polyestercomposition produced in melt is as low as possible, more preferably atmost 5 equivalents/ton. For the second factor also to improve thehydrolysis resistance of the polyester composition, it is important toprevent the additional carboxyl end groups of the polyester (a) formedthrough hydrolysis from increasing by reacting them with the glycidylcompound of the composition. Combining the two factors has led to thepresent invention. The carboxyl end group content of the polyestercomposition can be determined in a method of dissolving the polymer in asolvent followed by titrating the resulting polymer solution, or in amethod of quantitatively analyzing the polymer through high-resolutionNMR.

The polyester composition obtained according to the method of theinvention has good hydrolysis resistance and, when melted, gives littlegas emission and undergoes little viscosity change. Having suchadvantages, the polyester composition can be widely used for variousmolding materials, for example, for automobile parts, and parts ofelectric and electronic appliances, and it is especially favorable forconnectors for automobiles and electric and electronic appliances.

EXAMPLES

The invention is described in more detail with reference to thefollowing Examples. The methods for measuring the properties of thepolyester composition of the invention are mentioned below.

(1) Gas Generation:

Pellets of the composition are weighed, and left in a hot air drier at260° C. for 30 minutes. After taken out of the drier, they are againweighed. The weight loss indicates the quantity of gas generation fromthe sample.

(2) Mechanical Properties:

The sample is injection-molded into ASTM #1 dumbbell-shaped test pieces,and they are tested for the tensile yield strength at yield and thetensile strength at break according to ASTM D-638.

(3) Hydrolysis Resistance:

The test pieces are left in a pressure cooker tester at 121° C. and 100% RH for 200 hours. After taken out of the tester, they are tested forthe tensile strength at yield and the tensile strength at breakaccording to the method (2).

To determine the carboxyl end group content of the sample, the testpiece is dissolved in a solvent of o-cresol/chloroform, and theresulting solution is titrated by ethanolic potassium hydroxide.

(4) Melt Viscosity Stability:

According to ASTM D-1238, a load of 1 kg is kept applied to the sampleat 250° C. in a melt indexer, and the melt flow rate (MFR) of the sampleis measured after 5 minutes and 20 minutes.

EXAMPLES 1 TO 8, COMPARATIVE EXAMPLES 1 TO 11

100 parts by weight of PBT having an intrinsic viscosity of 0.89 dl/gand a carboxyl end group content of 36 eq/ton was blended in dry with aglycidyl ester compound, a glycidyl ether compound, other epoxy compoundand a catalyst in the ratio indicated in Table 1 below. The resultingblend was melt blended and pelletized through a 30-mmφ twin-screwextruder set at 250° C.

Using a screw-in-line injection-molding machine set at 250° C., theresulting pellets were molded into ASTM #1 dumbbell-shaped test pieces.The mold temperature was 80° C.

The data of the gas generation, the melt viscosity stability, themechanical properties and the hydrolysis resistance of each sample aregiven in Table 1. TABLE 1 Composition Glycidyl Ester Glycidyl EtherOther Epoxy Compound Compound Compound Catalyst Gas amount amount amountamount Emission type (parts) type (parts) type (parts) type (parts) wt.% Example 1 a-1 0.3 b-1 2.2 — — d-1 0.05 0.05 2 a-2 0.5 b-2 2.0 — — d-10.05 0.05 3 a-2 0.5 b-1 2.0 — — d-1 0.05 0.06 4 a-2 1.0 b-1 1.5 — — d-10.05 0.06 5 a-2 1.5 b-1 1.0 — — d-1 0.05 0.07 6 a-2 1.5 b-1 1.0 — — d-20.05 0.07 7 a-3 1.0 b-1 1.5 — — d-1 0.05 0.06 8 a-2 0.7 b-1 1.5 — — d-10.05 0.06 Comparative  1* — — — — — — — — 0.03 Example 2 a-2 1.0 — — — —— — 0.06 3 a-2 1.0 — — — — d-1 0.05 0.05 4 a-2 3.0 — — — — d-1 0.05 0.105 — — b-1 1.5 — — — — 0.05 6 — — b-1 1.5 — — d-1 0.05 0.04 7 — — b-1 3.0— — d-1 0.05 0.06 8 — — — — c-1 1.5 d-1 0.05 0.13 9 a-2 1.0 b-1 1.5 — —— — 0.07 10  a-2 1.0 — — c-1 1.5 d-1 0.05 0.15 11  — — b-1 1.0 c-1 1.5d-1 0.05 0.14 Carboxyl end group Tensile Yield Strength Content beforeafter before after MFR processed processed processed processed 5 min 20min in cooker in cooker retention in cooker in cooker g/10 min g/10 minMPa MPa % eq/t eq/t Example 1 26 22 55 52 95 5 21 2 29 25 55 53 96 4 193 31 33 55 52 95 4 20 4 32 35 54 50 93 3 18 5 31 35 54 49 91 2 21 6 3136 54 48 89 2 28 7 31 36 54 50 93 3 20 8 31 35 55 43 78 7 36 Comparative 1* 30 40 53 10 19 40 450 Example 2 30 40 53 11 21 14 211 3 30 40 53 1223 10 170 4 31 40 53 18 34 1 70 5 30 36 54 13 24 26 277 6 30 27 54 14 2618 184 7 30 24 55 19 35 10 86 8 30 23 54 18 33 11 96 9 31 39 54 25 46 662 10  30 35 54 39 72 2 32 11  30 20 55 20 36 10 90Notes in Table 1:*Not melted and pelletized, this was directly injection-molded.a-1: diglycidyl terephthalatea-2: glycidyl benzoatea-3: glycidyl versatateb-1: bisphenol A diglycidyl ether epoxy resinb-2: pentaerythritol polyglycidyl etherc-1: 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylated-1: sodium stearated-2: triphenyl phosphate

As is obvious from the data in Table 1, the samples of the polyestercomposition of the invention all have good hydrolysis resistance, andwhen melted, give little gas emission and undergo little viscositychange.

EXAMPLES 9 TO 16, COMPARATIVE EXAMPLES 12 TO 22

Polyester compositions were prepared in the same manner as in Example 1,for which, however, 20 parts by weight of glass fibers and 5 parts byweight of ethylene-ethyl acrylate copolymer were added to 100 parts byweight of PBT having an intrinsic viscosity of 0.82 dl/g and a carboxylterminal concentration of 40 eq/ton, along with the components indicatedin Table 2 below. Each polyester composition thus prepared herein wasextruded, molded and tested also in the same manner as in Example 1. Thedata are given in Table 2. TABLE 2 Composition Glycidyl Ester GlycidylEther Other Epoxy Compound Compound Compound Catalyst Gas amount amountamount amount Emission type (parts) type (parts) type (parts) type(parts) wt. % Example  9 a-1 0.3 b-1 2.2 — — d-1 0.05 0.06 10 a-2 0.5b-2 2.0 — — d-1 0.05 0.05 11 a-2 0.5 b-1 2.0 — — d-1 0.05 0.06 12 a-21.0 b-1 1.5 — — d-1 0.05 0.06 13 a-2 1.5 b-1 1.0 — — d-1 0.05 0.07 14a-2 1.5 b-1 1.0 — — d-2 0.05 0.08 15 a-3 1.0 b-1 1.5 — — d-1 0.05 0.0716 a-2 0.8 b-1 1.5 — — d-1 0.05 0.06 Comparative 12 — — — — — — — — 0.03Example 13 a-2 1.0 — — — — — — 0.06 14 a-2 1.0 — — — — d-1 0.05 0.05 15a-2 3.0 — — — — d-1 0.05 0.10 16 — — b-1 1.5 — — — — 0.05 17 — — b-1 1.5— — d-1 0.05 0.04 18 — — b-1 3.0 — — d-1 0.05 0.07 19 — — — — c-1 1.5d-1 0.05 0.14 20 a-2 1.0 b-1 1.5 — — — — 0.07 21 a-2 1.0 — — c-1 1.5 d-10.05 0.15 22 — — b-1 1.0 c-1 1.5 d-1 0.05 0.14 Carboxyl end groupTensile Yield Strength content before after before after MFR processedprocessed processed processed 5 min 20 min in cooker in cooker retentionin cooker in cooker g/10 min g/10 min MPa MPa % eq/t eq/t Example  9  97 100 65 65 4 20 10 10 6 100 66 66 2 18 11 11 12 100 60 60 2 19 12 11 1399 58 59 2 17 13 11 14 99 57 58 1 21 14 11 13 99 44 44 1 29 15 11 13 9950 51 2 19 16 11 13 100 42 42 6 36 Comparative 12 10 13 98 15 15 37 445Example 13 10 13 98 16 16 13 205 14 10 13 98 16 16 9 166 15 11 13 98 1717 0 65 16 10 12 99 16 16 24 262 17 10 8 99 17 17 17 178 18 10 6 100 2020 9 85 19 10 6 99 18 18 10 97 20 11 13 99 32 32 4 60 21 10 13 99 38 381 32 22 10 5 100 19 19 10 88Notes in Table 2:a-1: diglycidyl terephthalatea-2: glycidyl benzoatea-3: glycidyl versatateb-1: bisphenol A diglycidyl ether epoxy resinb-2: pentaerythritol polyglycidyl etherc-1: 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylated-1: sodium stearated-2: triphenyl phosphate

As is obvious from the data in Table 2, all the samples of the polyestercomposition of the invention, though containing glass fibers andethylene-ethyl acrylate copolymer, still have good hydrolysisresistance, and when melted, give little gas emission and undergo littleviscosity change.

1. An electrical connector comprising a molded body made from apolyester composition comprising a melt blended product of 100 parts byweight of a polyester (a), 0.1 to 3 parts by weight of a glycidyl estercompound (b), 0.5 to 3 parts by weight of a glycidyl ether compound (c)and 0.001 to 1 part by weight of a catalyst (d).
 2. The electricalconnector as claimed in claim 1, wherein the melt-blended productfurther contains from 1 to 100 parts by weight, relative to 100 parts byweight of the polyester (a), of an impact modifier (e).
 3. Theelectrical connector as claimed in claim 1, wherein the melt-blendedproduct further contains from 1 to 100 parts by weight, relative to 100parts by weight of the polyester (a), of a filler (f).
 4. The electricalconnector as claimed in claim 1, wherein the polyester (a) in thepolyester composition has a carboxyl end group content of at most 7equivalents/ton
 5. The electrical connector as claimed in claim 4,wherein the carboxyl end group content of the polyester (a) in thepolyester composition is at most 5 equivalents/ton.
 6. The electricalconnector as claimed in claim 1, wherein the glycidyl ester compound (b)has one glycidyl group in the molecule.
 7. The electrical connector asclaimed in claim 1, wherein the glycidyl ester compound (b) is aglycidyl ester of a saturated aliphatic monocarboxylic acid or aglycidyl ester of an aromatic monocarboxylic acid.
 8. The electricalconnector as claimed in claim 1, wherein the glycidyl ester compound (b)is a glycidyl benzoate or a glycidyl versatate.
 9. The electricalconnector as claimed in claim 1, wherein the glycidyl ether compound (c)has one or two glycidyl groups in the molecule.
 10. The electricalconnector as claimed in claim 1, wherein the glycidyl ether compound (c)is an aromatic glycidyl ether.
 11. The electrical connector as claimedin claim 1, wherein the glycidyl ether compound (c) is phenyl glycidylether or bisphenol A diglycidyl ether epoxy resin.
 12. The electricalconnector as claimed in claim 1, wherein the catalyst (d) is an organic,alkali metal or alkaline earth metal salt.
 13. The electrical connectoras claimed in claim 1, wherein the catalyst (d) is a salt of an organicacid having at least 6 carbon atoms with an alkali metal or an alkalineearth metal.
 14. The electrical connector as claimed in claim 1, whereinthe catalyst (d) is at least one of sodium stearate, potassium stearate,calcium stearate, magnesium stearate and sodium benzoate.
 15. Theelectrical connector as claimed in claim 1, wherein the polyester (a) isa polymer or copolymer obtained through condensation of at least onedicarboxylic acid or an ester-forming derivative thereof with1,4-butanediol or a mixture of said polymer and copolymer.